UBC and Hepatic fibrosis: To determine the importance of Ccn2/Ctgf gene in CCl4-induced liver fibrosis, we deleted exon 4 utilizing mice that were homozygous for the floxed-Ccn2/Ctgf allele and hemizygous for the ubc-Cre/Ert2 transgene according to our previous report (Pi et al. 2015).